If you use the 81 (or 85, whichever your bridge pickup is) almost exclusively and having two dead spots on your 5-way switch doesn't bother you then you probably don't need a 3 way switch although bear in mind this may or may not bother you in the near future especially should you decide to switch between the neck and bridge pickup (or both) more often and you play at a live setting.

As for the buss well...best try to contact EMG or the local EMG retailer at your location and ask if you can order the buss separately. If you can still get a hold of the guy who sold you the EMGs and ask him for the EMG buss then do so.